Fix several panics when initialization of an ISA or PC-CARD device fails:

o  Assign sc->an_dev in an_probe() (which isn't really a probe function in
   the standard newbus sense) as we may need it for printing errors.
o  Use device_printf() rather than if_printf() in an_reset() - this is
   called from an_probe() long before the ifp structure is initialised
   in an_attach().
o  Initialize the ifp structure early in an_attach() as we use if_printf()
   in cases where allocation of descriptors etc fails.

MFC after:	3 days
Rebase the PMC indices at 1, since PMC_SOFT is at 0.

MFC after:	1 week